Pump-controlling mechanism



R. CONRAD'ER Pm CONTROLM-NG MECHANISM I Filed Feb. 21-, 1922' 7 Sheets-Sheet 1 Jan. 5 1926.

- R. CONRADER PUMP CONTROLLING NECHAKISM 7 Sheets-Sheet 2 Filed Feb. 21, 1922 A TTORNE Y.

R. CONRADER PUMP CONTROLLING MECHANISM Filed Feb. 21, 1922 T Sheets-Sheet 5 M 2 m Y Z 45 u. 2? W I 6 A h 45 7ZZ 3 Z Z fa %1W- Jan. 5, 1926.- 1,568,499

R. CONRADER PUMP CONTROLLING MECHANISM Filed Feb. 21, 1922 'T Sheets-Sheet 4 abbomw y v Jan. 5 192s. w 1 1,568,499

, R. CONRADER v PUMP CONTROLLING MECQANISI- Filed Feb. v 21. v 1922 v "Sheets-Sheet 5 Jan. 5 1926.

R. CQNRADER PUMP CONTROLLING MECHANISM Filed Feb. 21, 1922' '7 Sh e ts-Sheet Gbbommy Jan. 5, 1926. 1,568,499"

R. CONRADER v PUMP CONTROLLING MECHANISM Filed Feb; 21', 1922 7 Sheds-Sheet 7 Patented rm-s. 1926.

tats-.499

UNITED STATES PATENT osrica.

RUDOLPH CONRADER, OF ERIE, PENNSYLVANIA.

PUMP-CONTRQLLING- MECHANISM.

Application filed. February 21, 1922. Serial No. 538,207.

To all whom it may concern.

Beit known that I, RUDOLPH CONRADER, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented new and useful Improvements in' Pump-Controlling Mechanism, of which the following is a specification.

This invention is designed to economically and efiiciently control compressors and pumps to adjustthem to variations in the output desired. In its preferred form the invention relates to a. compound compressor or pump. In carrying out the invention the capacity is stepped up or down by cut ting out separate units. As exemplified the invention is shown as a compressor having a high and low pressure cylinder and one end of the high pressure and one end of the low pressure cylinder are first unloaded.

Then the oppositeends of the high and low pressure cylinder are unloaded. This is accomplished in the present invention leaving the pressure. in the usual intercooler unchanged so that there is no loss through this source as the pumps or compressors are unloaded. I preferably effect the unloading by closing off the inlet and preferably supply relief valves for exhausting the cylinders after the inlet valves are closed.

loader so that the sequence in the action of the unloaders is assured. I further prefer to provide a means whereby the compressor, or pump, is positively unloaded regardless of the receiver pressure at the starting of the pump so that the motor which drives the pump can get under importance in motors exerting their full power only I when running at speed. The invention also involves other features which will be particularly described and pointed out in the claims.

In controlling the stepped unload-' The invention is illustrated in the accompanymg drawings as follows Fig. l-shows a side elevation of a com- PI'QSSOL.

Fig. 2 an end view of the same.

Fig. 3 a plan view, slightly enlarged.

Fig. 3 a plan view of a pipe connection.-

Fig. 3" a side elevation of an electric controlling switch.

Fig. 4 a sectional view on the line 44 in Fig. 5 of one of the unloaders.

Fig. 5 a section on the line 55 in Fig. 4. Fig. 6 a section on the line 6-6 in Fig. 5. Fig. 7 a side elevation, partly in section,

of the regulator unloading the first end of the cylinders.

Fig. 8 a section on the line 8-8 in Fig. 7.

Fig. 9a side elevation, partlyin section, of the regulator controlling the unloading of the second ends of the cylinders.

Fig. 10 a section on the line 10--10 in Fig. 9.

Fig. 11 a side elevation, partly in section on the line 11-11 in Fig. 12.

Fig. 12 a section on. the line 1212 in Fig. .11.

.Fig. 13 a side elevation, partly in section, of the low pressure'cylinder.

Fig. 14 a similar view of the high presi sure cylinder. 7 v

Fig. 15 a front elevation of the controlling rheostat and a sectional view of the con-.

trolling mechanism for unloading the compressors at the starting of-the motor.

Fig. 16 'a section on the line 16-16 in Fig. 15.

Fig. 17 an elevation of a spring for actuating the rheost-at lever.

1 marks the low pressure cylinder. 2 the high pressure cylinder, 8 the intercooler between the cylinders, 4 an electric motor driv- 'ing the compressor through the usual crank shaft and connecting parts (not shown), 5 the frame of the compressor, 6 the bed on which it is mounted, 7 the piston rod. 8 the piston operating in the low pressure cylinder, 9 intake valves of any ordinary construction, 10 discharge valves, 11 and 12 intake passages, these passages being separated by a wall 13, and 14 a face plate leading to the passages 11 and 12, the face plate having a closure face 15 corresponding to the partition 13. The purpose of thus dividing the intake is to permit of separate unloadeis for the opposite ends of the cylinders. The

arranged in cylinders 26 secured to the body 16 and have the inlet openings 27 with which the pipes leading from the regulatois are connected. The discharge valves 10 lead to the usual discharge passage 30 and this is connected by a pipe 31 with an intercooler 3. A pipe 32- .leads from the intercooler'to the'unloader' ;33. This unloader is exactly similar in construction to that shown Discharge valves 39 and 40 are provided,

in Figs. 4, 5 and 6 and has-the two controlled passages 33 and 33 leading to the inlet passages 34 and 34, these being separated, by a partition 34 and for the same reason as the partition 13 in the low pressure cylinder.- Inlet valves 35 and 36 operate in the usual manner from the passages 34 and 34 and a piston 38 is driven bythe piston rod 37 as part of the linkage to the motor.

these leading to a discharge passage 41 and the discharge passage. 41 leadsto a pipe 42 which is the final discharge from the pump or compressor. Relief valves 43, 44, 45 and 46 are provided for the ends 121, 2 and 2 respectively and in thecontemplated operation these are automatically opened as the unloaders for the several ends operate. These-relief valves are all the same in their detail construction and that construction is more articularly shown in Figs. 11 and 12. A b0 y.47 has the screw-threaded end 48 L which is secured in the end of the cylinder bringing the passage 49 into communication with the end of the cylinder; Avalve opening 50 leads from the passage 49' and this is controlled by a valve 51. The valve 51 is guided in a cylinder 52 anda very light 3 spring 53 tends to hold the valve in closed position, this valve acting during its reliefoperation as a check valve. A. discharge passage 54 leads from the cylinder 52 and a pipe55 leads from'this discharge passage to the atmosphere or to some point of discharge-in a liquid pump ordinarily to the intake. The spring 53- is tensioned against a fitting 56. A push pm 57 extends through a gland 58 carried by the fitting 56 in position to engage the valve. 51 and hold the same in closed position. A flange 59 extends from the fitting 56. This rests on the cylinder 52 and a cylinder 60 is mounted on top of the flange 59 and secured in place by screws 61. The push pin 57 has a shoul- (101' 62 with a screw-threaded extension 63. A cup 64 is placed over the shoulder 62 and is clamped against the shoulder by a nut 65 arranged on the screw-threaded end 63. A spring 66 of sufiicient strength to hold the valve 51 closed against the compres- 'sion of the cylinder is provided and operates against the end of the stem 57, the pressure of this spring bein adjustable by means of a plug 67 in the en of the cylinder 60. An inlet pipe 68 leads to the cylinder 60 and air or fluid underpressure is admitted to this cylinder whenever the corresponding unloader is M into action and this pressure acting un er the plunger formed by the cup 64 lifts the push pin 57 against the spring 66 and relieves the valve 51 of its pressure. The valve then readily opens as a check valve until the pressure in the cylinder is exhausted. Inasmuch as the inlet is closed the piston will then operate so far as this particular end of the cylinder is concerned in a partial vacuum. Two of the unloaders and the relief valves corresponding thereto are operated from one regulating valve. In the present instance the ends 1* and 2 are coupled together so as to distribute the load to the opposite ends of the cylinders. The regulator controlling these unloaders and relief valves is shown in Figs. 7 and 8. A body 69 has a controlconnection 70 leading to a pipe 71. This' pipe 71 leads to aside opening cross 72 and a 73 leads from this cross to the unloader controlling the end 1". A branch pipe 74 leads from the pipe 7 3 -to the relief valve 43. A pipe 75 leads from the cross 72 to the relief valve 45 and a branch pipe 76 leads from the pipe 7 5 to the uuloader controlling the passage 33 and consequently the end 2. A pipe 77 leads fromthe receiver (not shown) or from a a part having-receiver pressure as the pipe the body-69 and this opening leads to a port 78. The port 78 is in register with-a passage 79 in adiaphragm case 81 and leads to a diaphragm chamber 80. A diaphragm82 is mounted on the case 81 and clamped in position by a cover plate .83. A diaphragm button 84 engages a lever 85. The lever 85 is pivoted at 86 on an extension 83 on the cover plate 83. A spring 87 rests on a head 88 which exerts pressure on the lever 85 opposite the button 84 and the opposite end of the spring rests against an adjusting screw 89 by means of which the tension of thespring may be adjusted so as to give a counter-pressure desired so that the predetermined'pressure must be. delivered to the diaphragm in order 'toactuate the mechanism to unload one end of the compressors. The lever-85 is connected by a link 90 with a bell crank lever 91. The bell crank lever 91 is pivoted on the case 81 by means of a pin 92. One arm of the bell crank lever en- .42. This leads to the inlet opening 77 in" gages a yoke 93, this yoke being guided by the body (59. The yoke has the arms 94 which engage cross heads 95. The cross heads are drawn toward each other by springs 96 which extend from the cross heads to ears 97 on the body. The cross heads are secured to stems 98by nuts 99. A "alve 100 controls the opening from the passage or port 78 to a port 101.- The port 101 leads to an axial port 102 which communicates with the discharge. opening or end 70. An exhaust valve 103 controls a passage 104 leading from the port 102. The passage'104 connects with a port 105. This port is connected with a discharge opening 106 from which an exhaust pipe 107 leads to the starting mechanism hereinafter described.

,It will be observed that both valves are closed as shown in the drawings but it will be understood that this condition of the valves is only momentary. The end of the lever 85 is provided with a V-shaped cam 85" which engages a similar cam 85" on the lever 85. The lever 85 is pivoted on the case at 85 and a spring 85 operates against the.

lever 85. It will readily be seen that this cam action resists a movement of the lever 85 in either direction up to an intermediate or neutral point whenthe points of the cams pass each other and from that on assists the movement. The effect-of th s is .to prevent frequent reversals of the mechanism in that a pressure which will move the lever 85 against the action of the cams must be reduced'below such pressure before the counter-pressure device can return the mechanism against the pressure plus. the resistance of the spring 85 The valves, therefore, are both closed only momentarily and as the yoke 93 is moved in one direction, or the other, away from the cross heads 95 the springs 96 maintain the closure of the valve which is released by the movement of the feet or arms 94.

In the operation of the device when the pressure under the diaphragm rises above the pre-determmed pressure the lever 85 is lifted and. through the linkage heretofore described the valve 100 is opened permitting the receiver air to pass to the pipe 71 and thus to the unloaders controlling the ends 1 and 2 and to the relief valves 43 and Thus both these ends of the cylinders are unloaded and what air there is in the cylinders is unloaded. The pump then continues through the opposite ends of the cylinders through the intercooler in the usual manner. Broadly this regulator forms the subject matter of application #519,163 filed by me Dec. 1st, 1921, pressure controlled valve mechanism.

As the air or fluid is carried into the unloaders for these ends of the cylinders it is at the same time turned into the second regulator. This regulator is shown in decross heads 128.

tail in Figs. 9 and 1.0 and the air is de- .livered to this regulator through the pipe '71 l on the edges of the case and is clamped in position by a cover plate 110. A button 117 communicates the movement of the diaphragm to the lever 118. The lever118 is pivoted on a pin 119 mounted in an extension 116 extending from the cover plate. A spring 120 rests on a head 121 which in turn-engages the lever 118. This-spring rests against a screw 122 by means of which the force of the spring may be adjusted to the pressure which may be determined for the final unloading pressure of the pump or compressor. The lever 118 is connected by a link 123 with a bell crank lever 124, the bell crank lever being pivoted at 125. One arm of the bell crank lever engages a yoke 126, the yoke being guided by the body 110. The yoke has arms 127 which engage the These cross heads, are drawn inwardly by springs 129 extending from the cross heads to ears 130. Steins 131 are secured to'the cross heads 128 by.

nuts 132. A valve 133 controls an opening between the port 111 anda passage 134. The passage 134 leads to a port 135 and this leads to a discharge opening 136 through which a pipe 137 leads to the unloader controlling the end 1 of the low pressure cylin-- 139 leads from the pipe 138 to the. relief valve 46 on the same end of the high pres sure cylinder.

This regulator is provided with -mechamsm for preventing frequent reversals in Ill) the same manner as the first regulator described. The lever 118 has a V cam 118 operating in connection with the cam 118". The cam 118 is mounted on a lever 118 and this is pivoted on a pin 118 carried by the shell 114. A spring 118 operates against the lever 118 and gives it the desired pressure to make the difference between reversals anything desired.

The regulator operates substantially in the manner of the regulator heretofore described. When the pressure under the diaphragm reaches the final predetermined pressure for the compressor \the upward movement of the diaphragm acting through the mechanisms referred to opens the inlet valve 133, this putting air under pressur' predetermined pressure the spring 120 forcing down the lever 118 moves the yoke 126 so 'as to close the inlet valve 133 and open the exhaust valve 140.- Immediately, therefore, the relief valves 44 and 46 close under the influence of their springs and .the unloade rs controlling the ends 1" and 2" of the low and high pressure cylinders are opened so that the pumping is resumed by these cylinders. Vith another step in' thedrop of the pressure the first regulator-operates to closethe inlet valve 100 and to open the exhaust valve 103' so as to 'close the remaining relief valves and open the remaining unloaders so that the entire compressor is put into operation. It will be noted that during this unloading action either from one end of the cylinder, or both ends of the cylinder a discharge of air from the intercooler is prevented and it is maintained under the normal pressure so that there is no loss by reason of such discharge and on resumption of pumpingno jar, or excessive heating. Current is conducted to the motor through the lines 145 and a shunt 1'46 leads from this to an electro-magnet 147. A rheostat lever 148 operates over the contacts 149 in'the usual manner and when current is fully on' the lever 148 is held inposition by the magnet 147 and is automatically thrown .to starting position by'a spring 150 should the current fail in the magnet 147. This is ,the ordinary starting device and has the usual mounting 151.

A frame 152 is mounted on a standard 153 and this is carried by a floor plate 154 so as to properly adjust it to the mounting 151. Air is carried by the pipe 144 to the inlet port 155 ofa body 156 of a controllingdevice. The port 155 communicates with a vertical port 157 at the ends of which are the valve seats 158 and 159 controlled by valves 160 and '161 respectively. A stem 162 extends from the valve 161 and terminates in a head163. A'sprin'g164 operates against said head. Thespring and head are mounted in a shell 165, the lower shoulder 166 lim-, iting the expansion of the spring. The shell 165-is slidingly mounted in the frame 152 and terminates with a cap 167. This. cap is in-the path of a cam 168 on theend of the lever 148 and this cam is shaped to force the shell 165 downwardly to the limit of its movement when the lever 148 is in its-final position closing the circuit. In this posi-' tion it forces the valve 161 to its seat with the spring pressure of the spring 164. A stem 169 extends from the valve 160 and a spring 17 0 operates againstthe stem 169 and tends to'close the valve 160. Pins 171 extend between the valves 161 and 160 so that as one is closed the other is necessarily open. The spring 170 is of less strength than the spring 164 so that as the valve 161 is forced downwardly the valve' 160 is opened but as the cap 167 is released by the earn 168 the spring 170 is of sufficient strength to close the valve 160, at the same time opening the valve 161 and forcing the shell 165' 1113 wardly. In the initial position atstarting the valve 160 is (.lOCGd and the valve'161 opened. A port 1752 leads from the port 157 to the inlet end 173 of the body 156 and is conneeted by a pipe 174 with the receiver or pipe 77 so that this port is constantly under receiver pressure. \Vith the lever' 148 at starting position, therefore, receiver pressure passes byway of the port'157, the valve 160 being closed, and thence by the port 155 to the pipe 144 and into the exhaust sides of the regulator. If the receiver pressure is below the pie-determined pressure the exhaust valves in both regulators will be open and the inlet valves of these regulators closed. The receiver pressure, therefore, will pass-by way of. the exhaustvalves vinto the pipes leading to the several unloaders and relief valves so that with the starting of the motor regardless of receiver pressure the compressor will be unloaded as the motor starts. As the motor builds valve 160." This immediately opens the exup its speed. and the starting lever-is carried to its final position the cam with the last movement of the lever operates to reversevalves 160 and" haust sides of the regulator to the atmosphere by way of the port 175 which is connected by a discharge passage 176with the dlschargepipe 177 which may go to the atmosphere orv to the intake of the'compressorof any convenient point of discharge. If

.the receiver is below the pre-determined pressure then the inlet valves to the regulators willremain' closed and full pumping will immediately begin or if the pressure is at an intermediate point one setof unloaders may be opening so that one end of the cylinders may start pumping. a On the other hand if the receiver pressure is above the pre-determined pressureboth inlet valves will continue unloaded until the receiver pressure is reduced, the regulators operating in. the normal manner. Broadly the starting-mechanism just described formsthe subject matter of application #519,166 'filed by me Dec. 1st, 1921 electricmotor load controlling devices.

With these inlet unloaders used in con- .will be open and the cylinders as a whole cooler.

nection with a relief valve the cylinders are exhausted down to practically atmospheric pressure in the final clearance. The relief valves are an advantage in the final unloading even where this device is used with a single compressor and is of peculiar advantage where the pressure'is stepped up both for economy and saving as to the inter- The maintenance of the normal pressure in the intercooler during the unloading is desirable both for efiiciency and smoothness of running and the elimination of heat in the loading up. The manner of unloading the cylinders makes the comparative pumping of the two cylinders always equal so that a comparatively constant pressure is maintained in the intercooler which may be arranged at the most desirable pressure.

'It will .be noted that the relief valve with its screw-threaded fitting as 48, Fig. 12, is screwed into the indicator opening of both ends of said cylinders; unloaders for' said cylinders, said unloaders operating to close the intakes of each end of said cylinders independently; and means controlling said unloaders to operate one unloader of the low pressure cylinder in unison with one unloader of the high pressure cylinder and independently of the other ends of said cylinders and to unload the remaining ends of said cylinders in unison subsequently to the unloading of the first-mentioned ends.

2. 'In a pump controlling mechanism, the combination of a compressing cylinder having an inlet and discharge; an unloader closing the inlet of the cylinder; a relief valve discharging the cylinder to a pressure below a discharge pressure; and pressure actuated means controlling. saidv unloader and relief valve to actuate the same simultaneously.

V 3. Ina pump controlling mechanism, the combination of a pump cylinder having an inlet and discharge; an unloader closing the inlet of the cylinder; a relief valve discharging the cylinder to a pressure below a discharge pressure comprising a valve; a loading means for the valve; and a pressure actuated motor releasing the loading means. 4. In a pump controlling mechanism, the

combination of a pump cylinder having an inlet and discharge; an unloader closing the inlet of the cylinder; a relief valve discharging the cylinder to a pressure below a discharge pressure comprising a valve; a spring holding the valve normally closed; and a fluid actuated pressure device releasing the valve from the pressure of the spring.

, In a pump controlling mechanism, the combination of a pump cylinder having an inlet and discharge; an unloader closing the inlet of the cylinder; a relief valve discharging the cylinder to a: pressure below a discharge pressure comprising a valve body; a valve in the body; a fluid pressure cylinder; a pressure pin acting on the valve to close the same; a piston actingon the pressure pin; and a counter-pressure spring acting on the pressure pin to close the valve.

(i. In a pump controlling mechanism, the combination of a pump cylinder having an inlet and discharge; an unloader closing the inlet of the cylinder; a relief valve discharging the cylinder to a pressure below a discharge pressure comprising a valve body;- a valve in the body; a gland fitting; a cylinder mounted on the gland fitting; a pressure pin extending through the gland fitting into engagement with the valve; a piston in the cylinder operating on the pin and a springacting on the pin to close the valve.

7. In a pump controlling mechanism, the combination of a low pressure cylinder; a high pressure cylinder to which the low pressure cylinder discharges; an unloader closing the inlet for the low pressure cylinder; an unloader for the high pressure cylinder; and a-relief valve for the low pressure cylinder discharging to a lower pressure than the discharge of said cylinder.

8. In a pum controlling mechanism, the combination 0 a low pressure cylinder; at high pressure cylinder to which the low ressure cylinder discharges, said cylinders aving inlets. and discharges; unloaders closing the inlets to said cylinders; and relief valves discharging from said cylinders at a pressure below the discharge pressure of said cylinders.

9. In a pum controllingmechanism, the combination 0 a low pressure cylinder; a high pressure cylinder to which the low pressure cylinder discharges; an unloader closing the inlet for the low pressure cylinder; an unloader for the high pressure cylinder; a relief valve for the low pressure cylinder discharging to a lower pressure than the discharge of said cylinder; and pressure-actuated means for controlling the relief valve and inlet unloader simultaneously.

simultaneously.

11. In a pump controlling mechanism,

' the combination of a pump cylinder; a piston-discharging at both-ends of said cylinder; inlet unloaders for both ends of said cylinders; relief valves for both ends of said cylinders discharging to a pressure less than the discharge pressure; and means for unloading one end of said cylinder and actuating the relief valve at the same end of said cylinder independently of the unloader and relief valve at the opposite end of the cylinder. I e

12. In a pump controlling mechanism, the combination of a pump cylinder; a piston dischargingat bothends of said cylinder; inlet unloaders for both ends of said cylinder; relief valves for both ends of said cylinder discharging to a pressure less than the discharge pressure; and means for unloading and actuating the relief valve at each end of the cylinder simultaneously and the valve and unloader at one end of the cylinder subsequently to the valve and unloader at the other end of the cylinder..

13. In a pump controlling mechanism, the combination of a low pressure cylinder; :1 high pressure cylinder to which the low pressure cylinder discharges, said-cylinders having separate inlets to each end and discharges; unloaders closing the inlets to said cylinders; relief valves operating at each end of each cylinder to. pressures less than the discharge pressure of-said' cylinders; and means actuating the unloaderand relief valve at one end of the low pressure cylinders simultaneously with the unloader and relief valve at one end of the high pressure cylinder and independently of the action of the unloaders and relief valves at the opposite ends of said cylinders.

14. In a pump controlling mechanism,

the combination of a pump having a low pressure cylinder and a high ressure cylinder; a receptacle between he cylinders receiving the discharge from the low pressure cylinder and discharging to the high pressure cylinder; and an unloading mechanisnr for said cylinders acting on the inletscof said cylinders closing the receptacle to the cylinders during the period the unloading mechanism is operating.

15.-.In a pump controlling mechanism, the

combination of a low pressure pump; a

combination 0 high pressure pump; unloaders for said pumps;ia motor driving said pumps; a controlling device controlling said motor; and pneumatically actuated means actuated by the controllin device controlling the unloaders on bot at starting.

16. In a pum controlling mechanism, the a low pressure pump; a high pressure, ump, a motor driving said pumps; unloa ers normally controlled by the pumped fluid operating on said pumps; a controlling device controlling said motor;

, and. pneumatically actuated means actuated by the controlling device controlling the unloaders on the pumps unloading the same at starting independently of the'pumped pressure.

' 1 7 In a pump controlling mechanism, the combination of a pump, a pump cylinder; a piston in the cylinder pumping at both ends of the cylinder; independent unloaders for each end of the cylinder; means for actuating said unloaders independently; a

motor-driving the pump a controlling deviceffor the motor; and means actuated by the controlling device controlling both unloaders to unload both ends of the at the starting of the pump.

- 18. In a pump controlling mechanism, the combination of a pump; a cylinder; a piston in the cylinder pumping at both ends of the cylinder; unloaders for both ends cylinder pumps unloading-the. same of the cylinder; means actuated-by the pumped fluid for actuating saidunloaders to unload said ends of the cylinder succes- ,sively; a motor driving the pump; a controlling device'for the motor; and means. actuated by the controlling device for o crating-the unloaders at both ends of t e cylinder and independently of the pressure of the pumped fluid for starting the motor.

19. In a pump controlling mechanism,

the combination of a pump comprising a low; pressure cyllnder; a pump comprising ahigh pressure cylinder to which the low pressure cylinder discharges; pistons in said cylinder pumping at both ends of said cylinders; unloaders controlling the ends of both cylinders and operating independently on the ends of said cylinders; a motor driving said pumps; a controlling device for saidmotor; and means actuated by the controlling device for unloading both ends of.

both cylinders at the starting of the motor. 20. In a pump controlling mechanism, the

lit)

combination of a pump comprising a low pressure cylinder; a pump comprising a highv pressure. cylinder to which the low pressure cylinder discharges; pistons in said cylinders pumping at both ends of said cylinders; unloaders for each end of each cylinder, theljcunloader at one end of each cylinder operating independently of the unloader at the opposite end of the cylinder;

pressure actuated mechanism responsive to pumped fluid pressure actuating said un combination of a pump comprising a low pressure cylinder; a pump comprising a high pressure cylinder to which the low pressure cylinder discharges; unloaders for said cylinders; means responsive to pumped pressure tor normally controlling said unloaders; a motor driving said pumps; a controlling device for the motor; and pneumatically actuated means actuated by the controlling device unloading said pumps at the starting of the motorv 22. In a pump controlling mechanism, the combination of a pump; an unloader acting to unload the pump when subjected to pressure; a motor driving the pump; a controlling device for the motor: and means controlled by the device putting the unloader under pressure until the motor is started.

23L In a pump controlling mechanism, the combination of a pump; an unloader acting to unload the pump when subjected to pressure; a motor driving the pump; a controlling device for the motor; a regulator responding to pumped pressure normally controlling the unloader; and means controlled by the device putting the unloader under pressure until the motor is started.

24. In a pump controlling mechanism, the combination of a pump, an unloader acting to unload the pump when subjected to pressure; a motor driving the pump; a controlling device for the motor; a regulator responding to pumped pressure normally controlling the unloader; and means controlled by the device and acting through the regulator to put the unloader under pressure until the motor is started.

v 25. In a pump controlling mechanism, the combination of a pump; an unloader for.

said pump, said unloader acting when sub,- gectcd to pressure; a. regulator controlling the unloader having connections and inlet and exhaust valves therefor, the inlet valve normally controlling the pumpedpressure acting on the unloader; a motor driving the pump; a motor controlling device; a starting load controller comprising pressure controlled inlet and exhaustvalves; a pressure connection between the controller and the exhaust connection of the regulator; and means acting the controlling device is actuated for actuating the controller to ad- I init pressure to the exhaust connection with the controlling device in a position starting the motor.

26. In a pump controlling mechanism, the combination of a low pressure pump comprising a low pressure cylinder; a piston discharging at both ends of the cylinder; a high pressure pump to which the low pressure pump discharges con'lprising a cylmder; and a piston operating a pump at both ends of the cylinder; unloadcrs for each end of each cylinder; a regulator having inlet and exhaust connections and inlet and exhaust valves controlling the unloader of one end of a low pressure cylinder and one end of the high pressure cylinder; a regulator having inlet and exhaust connections and inlet and exhaust valves controlling the unloaders at the opposite ends of said cylinder, the second-mentioned regulator having its inlet leading from the firstarientioned regulator, the exhausts of said regulators being connected through a conduit with a load controller comprising inlet and exhaust valves; a motor driving sa id pumps; a controlling device for the motor: and means actuated by the controlling device actuating the controller to open the inlet valve thereof to deliver pressure to the exhaust connec tions of the regulators at the starting of the motor.

27. In a pump controlling mechanism. the

combination of a cylinder having separate inlet passages; an unloader having sepa-., rate passages communicating with the pa sages of the cylinder and a single inlet passage: and unloader controlling valves controlling the passages of the unloader.

28. In a pump controlling mechanisimthe combination of a cylinder having separate inlet passages; an unloader having separate passages communicating with the passages of the cylinder and a single inlet passage: unloader controlling valves controlling the passages of the unloader; and means for controlling said unloader valves independ ently. i

29. In a pump controlling mechanism, the combination of a cylinder having inlet passages adjacent to each other and with a surrounding joint face and a bridge face between the two passages; and an unloader having corresponding faces with separate passages therein leading to each passage of the cylinder.

30. In a pump controlling mechanism, the combination of a cylinder having inlet passages adjacent to each other and with a surrounding joint face and a bridge face between the two passages; and an unloader having corresponding faces with separate passages therein leading to each passage of the cylinder, the unloader having a single inlet pa sage. i

31. I. a pump controlling mechanism, the combination of a pump having a low pressure cylinder; a .high pressure cylinder; a receptacle between the cylinders receiving the discharge from the low pressure cylinder and discharging to the high pressure the combination of a pump having a low sure cylinder; a high pressure cylinder; a

receptacle between the cylinders 'receiving the discharge from the low pressure cylinder and discharging to the high pressure cylinder; an unloading mechanism for the low pressure cylinder acting on the inlet of said cylinder; an unloading mechanism for the high pressure cylinder, said mechanisms maintaining the receptacle pressure normal during the period the unloading mechanism is acting; and a relief device for the 'low pressure cylinder acting asthe cylinder is unloaded.

In a pump controlling, mechanism pressure cylinder and a high pressure cylinder; a receptacle between the cylinders receiving the discharge from the low pressure cylinder and discharging to the high pressure cylinder; an unloading mechanism acting on the inlets of said cylinders for said cylinders maintaining the receptacle pressure normal during the period the 1111' loading mechanism is acting; and relief devices for said cylinders acting on said-cylinders as they are unloaded.

34. In a pump controlling mechanism, the

. combination of a pumphaving a low pres- 4o sure cylinder and a high-pressure cylinder; a receptacle between the cylinders receiving -mechanism for the cylinders during the period the unloading mechanism is acting; and a relief device for the high pressure cylinder acting as said cylinder is unloaded.

35. In a pump controlling mechanism, the combination of a pump having a low pressure cylinder and a high pressure cylinder; a receptacle between the cylinders receiving the discharge from the low pressure cylinder anddischarging to the high pressure cylinder; an unloading mechanism for the" low pressure cylinder acting on the intake of the low pressure 0 linder; an unloading igh pressure c linder, said mechanisms closing the receptac e to the cylinders during the period the unloading mechanism is operating; and a relief device for the low pressure cylinder acting on the cylinder as it is unloaded.

36. In a pump controlling mechanism, the combination of a pumphaving a low pressure cylinder'and, a high pressurecylinder; a receptacle between the cylinders receiving the discharge from the low pressure cylinder and discharging to the high pressure cylinder; an unloading mechanism acting on the inlets of said cylinders for said cylinders closing the receptacle to the cylinders durmy hand.

I V RUDOLPH CONRADER.

so I 

